lucene merge policy in solr

["Zhang, Lisheng" <Li...@BroadVision.com>]

Hi,

In earlier lucene version it merges segements periodically
according to merge policy, when it reached merge time, indexing
request may take longer time to finish (in my test it may delay
10-30 seconds, depending on indexed data size).

I read solr 3.6 - 4.1 doc and we have entries in solrconfig.xml
to control segment merge. I am wondering if someone gives me
a very high-level confirmation: in solr 3.6 - 4.1, indexing could 
be delayed also when big merge happens, and before merging finishes
we cannot index (since collection is locked)?

Thanks very much for helps, Lisheng

Re: lucene merge policy in solr

[Erick Erickson <er...@gmail.com>]

I think you're on a slightly wrong track..... In Solr 4.1, merging is
done as a background task. In 3.x, an incoming indexing
request would block until the merge completed. In 4.1, all
your indexing requests should return immediately, any merging
will be carried out by background threads so you don't have to do
anything to get this functionality.

Here's a writeup:

http://www.searchworkings.org/blog/-/blogs/gimme-all-resources-you-have-i-can-use-them!/

Best
Erick


On Tue, Mar 5, 2013 at 9:18 PM, Zhang, Lisheng <
Lisheng.Zhang@broadvision.com> wrote:

> Hi,
>
> In earlier lucene version it merges segements periodically
> according to merge policy, when it reached merge time, indexing
> request may take longer time to finish (in my test it may delay
> 10-30 seconds, depending on indexed data size).
>
> I read solr 3.6 - 4.1 doc and we have entries in solrconfig.xml
> to control segment merge. I am wondering if someone gives me
> a very high-level confirmation: in solr 3.6 - 4.1, indexing could
> be delayed also when big merge happens, and before merging finishes
> we cannot index (since collection is locked)?
>
> Thanks very much for helps, Lisheng
>